Light Emitted Diode (LED) displays are becoming common for computer, television, tablet, and smart-phone screens. An LED is a type of diode that emits light in response an applied electric current. An LED display includes an array of LED cells, and an LED cell includes a group of LEDs, such as red, green, and blue LEDs. By varying the intensity of each of the LED in a cell, various colors can be produced. The multiple cells, or pixels, can form images and video to a human viewer.
Often, the fabrication of LEDs involves the coating of phosphors onto an LED die. A phosphor is a luminescent material. The phosphor is typically coated onto an LED die using a spray process. A shadow mask is used to expose certain regions of a number of LED dies to the spray process. The shadow mask is typically secured to a jig that holds a substrate having a number of LED dies, or another substrate holding the LED dies, through pins or screws. During the spray coating process, the shadow mask is susceptible to thermal expansion which can cause strain on the pins or screws used to secure the shadow mask. It is thus desirable to perform a spray coating process without causing too much stress on the thermal mask, which can lead to a lower quality coating.